Method of manufacture and assembly of fastening device



A. A. BlEN Jan. 18, 1966 METHOD OF MANUFACTURE AND ASSEMBLY OF FASTENINGDEVICE 2 Sheets-Sheet 1 Original Filed Jan. 18, 1961 INVENTOR. fi'Z/redI? 5Z6.

Jan. 18, 1966 A. A. BIEN 3,229,363

METHOD OF MANUFACTURE AND ASSEMBLY OF FASTENING DEVICE Original FiledJan. 18. 1961 2 Sheets-Sheet 2 A 25 f f a INVENZjOR. L fiZ/r'aa /Z 2386/1, E- BY m0 Q M-AZ 7 11:014

United States Patent 3,22 363 METHOD OF MANUFACTURE AND ASSEMBLY OFFASTENING DEVICE Alfred A. Bien, Dearhorn, Mich., assignor to ChryslerCorporation, Highland Park, Mich., a corporation of Delaware Originalapplication Jan. 18, 1961, Ser. No. 84,480.

Divided and this application June 15, 1961, Ser. No.

4 Claims. (Cl. 29432) This invention relates to a method of manufactureof a nut and its attachment to sheet material. This application is adivision of my application Serial No. 84,480 which was filed January 18,1961, now abandoned, which, in turn, was a continuation-in-part ofapplication Serial No. 32,434 filed May 27, 1960, now abandonded in thename of Alfred A. Bien, entitled Load Bearing Nut and Method ofManufacture and Assembly.

Heretofore the compression of two or more pieces or sections of sheetmetal has been accomplished by means of bolt and nut assemblies whereinno cooperating structure of the bolt and nut has been provided forcompressing the sheet metal pieces together at a considerable distancefrom the bolt shank on all sides thereof. The result is that the bolthead or washer thereunder ispulled toward the nut until either one pieceof the sheet metal is compressed between the bolt head and the nut andnot against the other sheet metal pieces, or until the bolt head and thenut bottom out against each other. The result is that the desiredimmovablity of the sheet metal sections caused by the clamping effect ofthe nut and bolt is not achieved and in the cases of automobiles andother structures undergoing considerable vibration, scratching andscreeching of the metal sections as they rub together and consequentloosening of the bolt and nut assembly become readily noticeable.

Another object is to provide novel methods for attaching the nut of theaforesaid assembly to one section of the sheet metal prior to itsassembly with the other sheet section or sections.

A specific object is to provide a nut blank having a tapered attachingpost for attachment of the nut to a plate by deformation of said postinto locking engage ment with the plate.

A further object is to provide die means for making the above attachmentof the nut to the plate.

Further objects and advantages of the present invention will becomeapparent from the following description and drawings in which:

FIGURE 1 is a cross-sectional view of the nut and bolt assembly of thepresent invention assembled with sheet metal sections;

FIGURE 2 is a plan view of the staked nut of FIGURE 1 taken along line2-2 in the direction of the arrows;

FIGURE 3 represents an initial stage of the assembly of the sheet metalto the nut;

FIGURE 4 represents the punching and sheet bending FIGURE 9 is a view ofFIGURE 8 taken along line 99 in the direction of the arrows;

FIGURE 10 is a view of FIGURE 8 taken along line 1010 in the directionof the arrows;

FIGURE 11 represents a variation in post design;

FIGURE 12 represents an intermediate attaching step of the nut of FIGURE11;

FIGURE 13 represents a variation in attaching post design;

FIGURE 14 is an end view of the attaching post of FIGURE 13;

FIGURE 15 represents a heading method for attaching the nut to apre-pierced sheet;

FIGURE 16 represents novel die structure and the initial step inattaching a nut to a pre-pierced sheet;

FIGURE 17 represents the completed operation of FIGURE 16; and

FIGURE 18 represents a single die punching and attaching operation.

Referring to the drawings, sheet metal sections 10 and 12 are clampedtogether by nut 14 and bolt 16. The bolt is of conventional structurehaving a head 18 and a threaded shank 20. A Washer 22 of any desiredthickness may be employed underneath the head 18, or the head 18 itselfmay be made of any desired dimension so as to eliminate the need for awasher. The nut 14 which may be rectangular as shown in FIGURES 1-5 orcircular as shown in FIGURE 6 or of any other desired shape includingdisc shape is comprised of a threaded portion 24, an attaching post 25,a connecting portion 26, and a fiange or load bearing portion 28. Thesloping portion 27 of post 25 may be arcuate as shown in FIGURES 110 ormay be straight as shown in FIGURE 16. If it is arcuate, less frictionis developed in bending the sheet 10 to the bottom of recess 35. The nutis preferably of steel that is work hardenable. As shown in FIGURES 1Soutward end 15 of post 25 does not extend beyond the plane of bearingportion 28 and will not, therefore, bottorn out against sheet 12 shouldsaid sheet be misaligned as shown in FIGURE 1. It is obvious, however,that sheet 12 would not bottom out against end 15 of attaching post 25if end 15 is just below the plane of sheet 12, and where sheet 10 is ofrelatively thick metal as shown in FIGURES 7l7, the projection of end 15slightly above bearing portion 28 would not impair the operation of thenut and in fact would facilitate the punching of the slug 31 from sheet10. It is further obvious that as the thickness of sheet 10 decreasesthe end 15 must be lowered with respect to portion 28 since the distancebetween sheet 12 and end 15 also decreases and a slight amount ofpulling through of Washer 22 would then cause bottoming out of thewasher and sheet 12 on end 15. Moreover, if the washer 22 is relativelythick and unyielding, end 15 may then be moved closer to sheet 12 sincethe chances of bottoming out decreases.

In attaching nut 14 to sheet metal 10 a double acting punch 30 isprovided and comprises an inner sleeve 32 reciprocable in an outersleeve 34. Both sleeves are formed to correspond to the shape ofattaching post 25 whether it be of the shape of FIGURES 2, 6, 8, 14, orsome other shape. The post 25 is provided with a straight or curvedsloping portion 27 which being larger in diameter than sleeve 32 isformed thereby into a shoulder 29 (FIGURE 1) as explained below.

The first step in attaching any of the nuts shown to a sheet by theself-piercing technique is to cause sleeve 32, in cooperation with post25, to punch a slug 31 from sheet 10. It is to be understood that thenut is supported on an anvil during the piercing and forming operationsdescribed herein. The use of an anvil follows general commercialpractice. Sleeve 32 is then idled as shown in FIGURE 4 while sleeve 34bends the flange 33 of sheet 10 tightly into the recess 35 in the nut.actuated as shown in FIGURE 5 to stake or forge the sloped portion 27into the shoulder 29. As much of slope 27 may be used to form shoulder29 as is necessary Sleeve 32 is then to hold sheet 10 onto the nut andit is obvious that shoulder 29 need not extend all the way around post25. Sleeve 33 may have a recessed bore 37 as shown to facili tateremoval of the slugs 31. The flat portion 39 of the post in FIGURE 6 isprovided to prevent rotation of the nut in the sheet 10.

The sheet metal 12 is provided with a relatively large aperture 40 sothat the normal misalignments of the sheet metal during assembly onautomobiles, for example, can be compensated for without having toprovide new apertures at considerable cost and at the expense ofstructural soundness.

The large aperture 40 would normally allow the nut and bolt to bottomout either against themselves or against one section of the sheet metal,but, as shown in applicants FIGURE 1 the washer 22 and flange portion 28of the nut compress between them the sheet metal 10 and 12 and there isno chance for the washer 22 and the nut 14 to bottom out againstthemselves or a single section of the sheet metal.

As shown in FIGURES 8l0, a plurality of projections 42 may be providedon the edge 44 of the nut recess 35 or any place on face 28 or recess35.

In FIGURES l3 and 14 a straight post 46 is shown provided with splines48 into which the edge 50 of apertured sheet 10 may be extruded toprovide anti-rotation structure. The post 46 may then be headed over inany number of ways, examples of which are shown in FIGURES l5 and 17.

The die structures shown in FIGURES 15-17 are espeially useful inattaching nuts to sheets having attaching post holes pre-punchedtherein. It is noted, however, in FIGURE 18 that the single die 52 canpunch the aperture in the sheet and also deform the post into lockingengagement with the sheet.

In FIGURES ll and 12, the nut post 25 is provided with a groove 52 intowhich the edge of sheet 10 is extruded prior to the final forgingoperation of die 32 as shown in FIGURE 5.

It has been found that the compression of the two or more sections ofsheet metal by this nut and bolt arrangement is of a magnitude farexceeding that achieved by conventional nuts and bolts when used onsheet metal of the construction shown herein.

I claim:

1. A method of attaching a metal nut to a deformable sheet wherein thenut is provided with a recessed face portion and a centrally threadedattaching post projecting from the recess and having an exterior surfaceand a ratr dially enlarged lower portion, comprising the steps ofplacing said sheet over the outer end of said attaching post, forcing afirst hollow die over said end of said post to punch a slug from saidsheet to define an aperture, moving a second hollow die surrounding saidfirst die to force portions of said sheet adjacent the above mentionedaperture into the recess in the nut face to points adjacent said lowerportion of said post, and subsequently moving said first hollow die todeform metal from the exterior surface only of said post and force suchdeformed metal into overlying position with respect to said portions ofsaid sheet around the margin of the slug aperture.

2. A method of attaching a metal nut to a deformable sheet wherein thenut is provided with a recessed face portion and a centrally threadedattaching post project ing from the recess and having an exteriorsurface and a radially enlarged lower portion, comprising the steps ofplacing said sheet over the outer end of said attaching post, forcing afirst hollow die over said end of said post to punch a slug from saidsheet to define an aperture,

interrupting movement of said first hollow die, moving a second hollowdie surrounding said first die to force portions of said sheet adjacentthe above mentioned aperture into the recess in the nut face to pointsadjacent said lower portion of said post, and subsequently resumingmovement of said first hollow die to deform metal from the exteriorsurface only of said post and force such deformed metal into overlyingposition with respect to said portions of said sheet around the marginof the slug aper ture.

3. A method of attaching a metal nut to a panel where in the nut has asurface defining a load carrying portion surrounding a depression fromwhich a centrally threaded attaching post having a radially enlargedlower portion projects, such method comprising the steps of placing theabove mentioned nut surface in face to face relationship with a firstside of said panel and supporting the nut, forcing a hollow tool havingan internal contour complementary to the contour of the terminal portionof said post against the remote side of said panel in'axial alignmentwith said post to punch a slug from said panel to provide an opening inthe panel penetrated by said post and accommodate disposal of the sluginto the interior of the hollow tool, imparting continued movement tosaid. tool to deform portions of said panel adjacent the punched openinginto the above mentioned depression and by means of such continued toolmovement forcing the above mentioned load carrying portion of said nutinto abutting relation with the first side of said panel, and utilizingmovement of said tool to deform metal from the exterior of the enlargedlower portion only of said post and forcing such deformed metal intooverlying relation with the margin of such deformed panel portionssurrounding the above mentioned opening to secure the nut to said panel.

4. A method of attaching a metal nut to a panel wherein the nut has asurface defining a load carrying portion surrounding a depression fromwhich a centrally threaded attaching post having a radially enlargedlower portion projects, such method comprising the steps of placing theabove mentioned nut surface in face to face relationship with a firstside of said panel and supporting the nut, forcing a hollow toolmechanism having an internal contour complementary to the contour of theterminal portion of said post against the remote side of said panel inaxial alignment with said post to punch a slug from said panel toprovide an opening in the panel penetrated by said post and accommodatedisposal of the slug into the interior of the hollow tool mechanism,imparting continued movement to at least a portion of said toolmechanism to deform portions of said panel adjacent the punched openinginto the above mentioned depression and by means of such continuedmovement of said tool portion forcing the above mentioned load carryingportion of said nut into abut-ting relation with the first side of saidpanel, and utilizing movement of the portion of said tool mechanismhaving the above mentioned complementary internal contour to deformmetal from the exterior of the enlarged lower portion only of said postand forcing such deformed metal into overlying relation with the marginof such deformed panel portions surrounding the above mentioned openingto secure the nut to said panel.

WHITMORE A. WILTZ, Primary Examiner.

4. A METHOD OF ATTACHING A METAL NUT TO A PANEL WHEREIN THE NUT HAS ASURFACE DEFINING A LOAD CARRYING PORTION SURROUNDING A DEPRESSION FROMWHICH A CENTRALLY THREADED ATTACHING POST HAVING A RADIALLY ENLARGEDLOWER PORTION PROJECTS, SUCH METHOD COMPRISING THE STEPS OF PLACING THEABOVE MENTIONED NUT SURFACE IN FACE TO FACE RELATIONSHIP WITH A FIRSTSIDE OF SAID PANEL AND SUPPORTING THE NUT, FORCING A HOLLOW TOOLMECHANISM HAVING AN INTERNAL CONTOUR COMPLEMENTARY TO THE CONTOUR OF THETERMINAL PORTION OF SAID POST AGAINST THE REMOTE SIDE OF SAID PANEL INAXIAL ALIGNMENT WITH SAID POST TO PUNCH A SLUG FROM SAID PANEL TOPROVIDE AN OPENING IN THE PANEL PENETRATED BY SAID POST AND ACCOMMODATEDISPOSAL OF THE SLUG INTO THE INTERIOR OF THE HOLLOW TOOL MECHANISM,IMPARTING CONTINUED MOVEMENT TO AT LEAST A PORTION OF SAID TOOLMECHANISM TO DEFORM PORTIONS OF SAID PANEL ADJACENT THE PUNCHED OPENINGINTO THE ABOVE MENTIONED DEPRESSION AND BY MEANS OF SUCH CONTINUEDMOVEMENT OF SAID TOOL PORTION FORCING THE ABOVE MENTIONED LOAD CARRYINGPORTION OF SAID NUT INTO ABUTTING RELATION WITH THE FIRST SIDE OF SAIDPANEL, AND UTILIZING MOVEMENT OF THE PORTION OF SAID TOOL MECHANISMHAVING THE ABOVE MENTIONED COMPLEMENTARY INTERNAL CONTOUR TO DEFORMMETAL FROM THE EXTERIOR OF THE ENLARGED LOWER PORTION ONLY OF SAID POSTAND FORCING SUCH DEFORMED METAL INTO OVERLYING RELATION WITH THE MARGINOF SUCH DEFORMED PANEL PORTIONS SURROUNDING THE ABOVE MENTIONED OPENINGTO SECURE THE NUT TO SAID PANEL.